Bat with composite handle

ABSTRACT

A bat has an elongate tubular striking member of a first material, and an elongate handle member of a second material. The handle may be of composite material laid up in selected layers and orientation to produce selected weight distribution, strength, and stiffness and improved batting capabilities. The striking member and handle member may have juncture sections which are substantially rigidly interconnected through mating configurations.

FIELD OF THE INVENTION

This invention relates to a ball bat, and more particularly to a ballbat with a striking barrel member made to provide desired strikingcapabilities, and a handle member made to provide desired swingingcapabilities, and a method for manufacturing such which produces a rigidinterconnection between the barrel and handle members.

BACKGROUND AND SUMMARY OF THE INVENTION

Tubular metallic baseball bats are well known in the art. A familiarexample is a tubular aluminum bat. Such bats have the advantage of agenerally good impact response, meaning that the bat effectivelytransfers power to a batted ball. This effective power transfer resultsin ball players achieving good distances with batted balls. Anadditional advantage is improved durability over crack-prone woodenbats.

Even though presently known bats perform well, there is a continuingquest for bats with better hitting capabilities. Accordingly, oneimportant need is to optimize the impact response of a bat. Further, itis important to provide a bat with proper weighting so that its swingweight is apportioned to provide an appropriate center of gravity andgood swing speed of impact components during use.

Generally speaking, bat performance may be a function of the weight ofthe bat, distribution of the weight, the size of the hitting area, theeffectiveness of force transfer between the handle and the strikingbarrel, and the impact response of the bat. The durability of a batrelates, at least in part, to its ability to resist denting or crackingand depends on the strength and stiffness of the striking portion of thebat. An attempt to increase the durability of the bat often produces anadverse effect on the bat's performance, as by possibly increasing itsoverall weight and stiffness, or having less than optimum weightdistribution.

It has been discovered that a hitter often can increase bat speed byusing a lighter bat, thereby increasing the force transferred to theball upon impact. Thus it would be advantageous to provide a bat havinga striking portion which has sufficient durability to withstand repeatedhitting, yet which has a reduced overall bat weight to permit increasedbat speed through use of an overall lighter weight bat.

It also has been discovered that greater hitting, or slugging,capability may be obtained by providing a bat with a handle made of amaterial different from the material of the striking portion or formedin such a manner as to have different capabilities. One manner forproviding such is to produce a bat with a composite handle, wherein thecomposite material may be structured to provide selected degrees offlexibility, stiffness, and strength. For example, in one hittingsituation it may be best to have a bat with a more flexible handle,whereas for other hitting situations it is advantageous to have a handlewith greater stiffness.

An example of a prior attempt to provide a bat with a handle connectedto a barrel section is shown in U.S. Pat. No. 5,593,158 entitled “ShockAttenuating Ball Bat.” In this patent an attempt was made to produce abat with handle and barrel member separated by an elastomeric isolationunion for reducing shock (energy) transmission from the barrel to thehandle, and, inherently from the handle to the barrel. Accordingly, sucha design does not allow for maximum energy transfer from the handle tothe barrel during hitting. As a result, the bat produces less energytransfer or impact energy to the ball due to the elastomericinterconnection between the handle and barrel.

Therefore there is a continuing need for a bat that provides theflexibility of a separate handle member and striking member andmaximizes the energy transfer between the two members.

The present invention provides an improved bat with a striking portionwith good durability and striking capabilities and a handle portion withdesirable weight and stiffness characteristics to permit greater batspeed during hitting.

One embodiment of the invention provides a bat having an elongatetubular striking member with a juncture section which converges inwardlytoward the longitudinal axis of the bat on progressing toward an end ofthe striking member, and an elongate handle member having an end portionthereof which is firmly joined to the converging end portion of thestriking member to provide a rigid interconnection therebetween topermit substantially complete striking energy transfer between thehandle member and the striking member.

In another embodiment, the bat has an elongate tubular striking memberhaving a juncture section adjacent its proximal end, the striking memberbeing composed of metal having a first effective mass, and an elongatehandle member composed of a material having a second effective masswhich is less than the first effective mass of the striking member, thehandle member having a juncture section adjacent its distal end, withthe juncture sections of the striking member and handle memberoverlapping and being joined together to provide a rigid interconnectiontherebetween to permit substantially complete striking energy transferbetween the striking member and the handle member on hitting. Becausethe handle member is of a lower effective mass it will help to produce alighter weight bat with the possibility of a greater swing speed.

The present invention provides a novel bat and method for producing thesame wherein the striking portion is comprised of the most appropriate,or optimum, structure for striking and the handle is comprised of themost appropriate, or optimum, structure for swinging, and the two arejoined for optimum slugging capability.

The present invention provides a bat, and method for making a bat,wherein selected materials are used in selected portions of the bat toachieve proper weight, or mass, distribution for optimum swing speed andto provide desired strength and stiffness of selected portions.

The present invention contemplates producing a handle member withmultiple composite layers which are appropriately oriented and joined toprovide a handle which has selected strength and stiffness. By providinga bat with a handle member made of composite material which may be laidup in multiple layers with selected orientation and strength, the handlemember may be structured to provide selected degrees of strength,flexibility, and vibration transfer in an assembled bat.

In one embodiment, one of the juncture sections of the striking memberor the juncture section of the handle member has projections thereonwhich extend radially from remainder portions of the juncture section adistance substantially equal to the thickness of a desired layer ofadhesive to join the striking member and handle member. Such projectionsfirmly engage the facing surface of the other member and this, inconjunction with the adhesive applied between the two members, providesa firm interconnection therebetween.

An object of the present invention is to provide a method for producingan improved bat having characteristics as set out above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view through the longitudinal center of a bat inaccordance with one embodiment of the invention.

FIG. 2 is a magnified sectional view of a juncture section of the bat ofFIG. 1.

FIG. 3 is a cross sectional view taken generally along the line 3—3 inFIG. 2.

FIG. 4 is a view taken generally along the line 4—4 in FIG. 2, with aportion of the striking member broken away.

FIG. 5 is a view similar to FIG. 4, but with a different ribconfiguration.

FIG. 6 is a magnified sectional view of a portion of the handle takengenerally along the line 6—6 in FIG. 2.

FIGS. 7-9 are perspective views of a flared end portion of the handlewith forming members associated therewith during the production of thehandle member to produce projecting ribs on the juncture section of thehandle.

FIG. 10 is an enlarged longitudinal cross section of a handle member asmay be used in the bat of FIG. 1, with portions broken away toillustrate composite lay up of the handle member with multiple compositematerial layers disposed at various regions along the length of thehandle and with some sections of the handle having more layers thanothers and being composed of different materials to obtain selectedhandle member mass, strength and stiffness characteristics.

FIG. 11 is a side elevation view of a test fixture for testing thebending strength of a handle member with an exemplary handle membermounted therein for testing.

FIG. 12 is a side elevation view of a test fixture for testing thebending strength of a full length assembled bat with an exemplary handlemember mounted therein for testing.

DETAILED DESCRIPTION

Referring to FIG. 1, an elongate tubular ball bat 10 having alongitudinal axis, or centerline, 20 comprises an elongate tubularstriking member 12. The striking member has a proximal, or inner, end 12a and a distal, or outer, end 12 b. A striking region 14 is disposedintermediate ends 12 a, 12 b. A frusto-conical juncture section 16 ofthe striking member adjacent end 12 a converges toward centerline 20 onprogressing toward end 12 a.

In the embodiment illustrated in FIGS. 1 and 2 striking region 14 has asubstantially cylindrical inner cavity, with an inner diameter D₁. Acylindrical tubular insert 22 is received in the striking region cavityto form a multiple-wall bat. The insert has proximal, or inner, anddistal, or outer, ends 22 a, 22 b, respectively. End 22 a is disposedadjacent juncture section 16. The bat also could be made as asingle-wall bat without insert 22.

Juncture section 16 has a major diameter equal to D₁ and a minordiameter noted D₂ at its end 12 a.

An elongate tubular handle member 30 is secured to and projectslongitudinally outwardly from end 12 a and juncture section 16 of thestriking member.

The assembled bat 10 has an overall length L₁. Striking member 12 has alength L₂ and handle member 30 has a length L₃. As seen lengths L₂ andL₃ are each substantially less than L₁.

The handle member 30 in the illustrated embodiment may be made of acomposite material or other appropriate material as will be discussed ingreater detail below. It has opposed distal, or outer, end 30 a, andproximal, or inner, end 30 b. The handle member has an elongate, hollow,tubular, substantially cylindrical gripping portion 32 of a diameter D₃throughout a major portion of its length, and a frusto-conical juncturesection 34 adjacent end 30 a. As best seen in FIGS. 1 and 2, juncturesection 34 diverges outwardly from the longitudinal axis in aconfiguration complementary to the converging portion of juncturesection 16 of the striking member. Juncture section 34 has a minordiameter D₃ (less than D₂), a major diameter D₄ (greater than D₂, butless than D₁), and a length which is no greater than 25% of the overalllength L₁ of the assembled bat.

End 12 a of striking member 12 provides an opening with a diameter D₂greater than diameter D₃ of gripping portion 32 of handle member 30. Thediverging portion of juncture section 34 of the handle member is suchthat the outer surface of juncture section 34 is substantiallycomplementary to the configuration of the inner surface of juncturesection 16 of the striking member so that they may fit in close contactwith each other when assembled as illustrated in FIGS. 1 and 2.

Referring to FIGS. 3 and 4, it will be seen that juncture section 34 ofthe handle member in the illustrated embodiment has a plurality ofelongate, radially extending ribs, or projections, 40 on its outersurface. These ribs extend substantially longitudinally of the handlemember, and are spaced apart circumferentially substantially equallyabout juncture section 34, or at approximately 120° from each other asillustrated.

Projections, or ribs, 40 extend outwardly from remainder portions of thejuncture section of the handle member a distance substantially equal tothe thickness of a layer of adhesive which it is desired to applybetween juncture section 16 of the striking member and juncture section34 of the handle member to secure these two members together to form thecompleted bat. It has been found desirable to apply a layer of adhesivebetween the juncture sections of the handle member and the strikingmember which is in a range of 0.001 to 0.010 inch thick, and preferablywithin a range of 0.002 to 0.005 inch thick. Thus ribs 40 projectoutwardly from remainder portions of juncture section 34 a distance in arange of 0.001 to 0.010 inch and more preferably in a range of 0.002 to0.005 inch.

When assembled as illustrated in the drawings, the outer surfaces ofprojections 40 firmly engage the inner surface of juncture section 16 ofthe striking member, with a layer of adhesive filling the space betweenthe circumferentially spaced ribs, or projections, to adhesively jointhe striking member to the handle member in this juncture section. Alayer of such adhesive is indicated generally at 42.

Although projections 40 are shown as formed on the handle, it should berecognized that projections formed on the inner surface of the juncturesection of the striking member and extending radially inwardly fromremainder portions of the striking member could be used also.

FIG. 4 illustrates an embodiment of the invention in which the ribs 40are substantially straight, and extend longitudinally of the handlemember. FIG. 5 illustrates another embodiment in which the ribs 46 arecurved, such that they extend somewhat helically about the outer surfaceof juncture section 34. They function similarly to ribs 40.

Although the projections, which may be formed on the external surface ofthe juncture section of the handle or on the internal surface of thejuncture section of the striking member, have been illustrated anddescribed generally as elongate ribs, it should be recognized that thepurpose of such projections is to provide a firm contacting engagementbetween the juncture section portions of the handle member and strikingmember to produce a substantially rigid interconnection therebetween.Thus, the projections do not necessarily have to be elongate ribs asillustrated. Instead, there could be a plurality of projections ofsubstantially any shape extending outwardly from remainder portions ofthe juncture section of the handle member or projecting inwardly fromthe inner surface of the juncture section of the striking member, or anycombination thereof, such that firm interengagement is provided betweenthe striking member and the handle member. For example the projectionsmay be a pebbled surface configuration, criss-crossed ribs, irregularlyshaped ribs, or any other configuration that provides a plurality ofraised surfaces for direct contact with the other member to provide asubstantially rigid interconnection between the handle member and thestriking member.

The complementary converging and diverging configurations of thejuncture sections of the striking member and handle member prevent thetwo parts from being pulled apart longitudinally in opposite directions,such as by pulling outwardly on opposite ends of the bat. The adhesiveis provided to inhibit longitudinal movement of the handle member andstriking member upon application of forces thereagainst such as mightoccur if forces were exerted at opposite ends of the bat in an attemptto compress them toward each other.

Although adhesive has been noted as a means for securing the two membersagainst relative longitudinal movement in the one direction, it shouldbe recognized that other means could be used also. For example,mechanical locking means of various types could be employed. Althoughnot shown herein, the striking member or handle member could be formedwith a radially projecting lip which engages a portion on the othermember when the parts are moved into the positions illustrated in FIGS.1-4 to prevent longitudinal separation of the members.

Further, although it has been mentioned that adhesive can fill thespaces between the projections, it is not necessary that the spacesbetween the projections always be filled, and a less than fillingquantity of adhesive may be adequate.

When assembled as illustrated in the drawings, juncture section 34 ofthe handle member fits tightly within juncture section 16 of thestriking member and a layer of adhesive interposed therebetween rigidlyinterconnects the striking member and handle member.

The fully assembled bat as shown in FIG. 1 includes a knob 48 secured tothe proximal end 30 b of the handle member and a plug 50 inserted in andclosing the distal end 12 b of the striking member. Referring to FIG. 1,a weighted member, or plug, 54 is inserted and secured in the proximalend portion of handle member 30. The structure and function of member 54will be described in greater detail below.

A generally cylindrical transition sleeve 52 having a somewhatwedge-shaped cross section as illustrated in FIG. 2 is secured to handlemember 30 to abut end 12 a of the striking member to produce a smoothtransition between end 12 a of the striking member and the outer surfaceof handle member 30. Rather than applying a transition sleeve 52, theproximal end 12 a of juncture section 16 of the striking member may beswaged to a gradually thinner edge region with a rounded proximal edge.

Describing a method by which the bat illustrated in the figures may beproduced, striking member 14 is formed of a material and in a manner toprovide desired impact, or striking capabilities. The striking membermay be formed by swaging from aluminum tube (or other metal foundappropriate for the striking region of a bat) to yield an integralweld-free member. While swaging is one means of producing such strikingmember, it should be understood that other methods of manufacturingmight work equally as well.

The striking member is formed with a circular cross section having astriking region which has a cylindrical interior surface defining aninterior cavity of a first selected cross sectional dimension, ordiameter, D₁. This produces a striking member having a first effectivemass. The effective mass may be a function of the specific gravity ofthe material, size, thickness, or other characteristics.

The juncture section 16 converges inwardly toward longitudinal axis 20to an opening at end 12 a having an internal diameter indicated D₂ whichis less than D₁.

Insert 22 has an outer diameter corresponding generally to, but possiblyslightly smaller than, D₁ such that it may be inserted into the strikingportion 14 of striking member 12. Its proximal, or inner, end 22 a mayengage the beginning of the inward converging portion of juncturesection 16 which prevents the insert from shifting further toward end 12a of the striking member. End 12 b of the striking member 12 is bentover to form a circular lip with a bore extending therethrough. An endplug 50 is placed in the end of the bat to engage end 22 b of the insertto hold it in place.

The striking member 12 may be formed of tubular metal material of afirst specific gravity, which may be, but is not limited to, aluminum,steel, titanium, or other suitable metal material. The striking memberalso might be formed of composite or other suitable materials. Insert 22also may be made of any such tubular metal or a composite. The insertserves a function as set out in prior U.S. Pat. Nos. 5,415,398 and6,251,034. Since the striking member is formed separately from thehandle member, the striking member may be formed in such a manner andfrom such materials as to produce the desired, or optimum, impact, orstriking capabilities. Thus the requirements of the striking member andhandle member are decoupled permitting each to be made of such materialsand in such a manner as to provide optimum point location of mass in thebat and optimum strength and stiffness or flexibility where needed.

The handle member may be formed from material which produces adifferent, and generally a lower, effective mass than it would have ifcomposed in a manner or of a material similar to that from which thestriking member is formed. The different effective mass of the handlemember may be a function of the specific gravity of the material formingthe striking member, its size, thickness or other characteristics. Forexample the material of the handle member may have a different specificgravity than the material from which the striking member is formed.

In some instances the handle member may be formed of a compositematerial, such as carbon fiber, having a second specific gravity lessthan the first specific gravity of the striking member. In otherinstances the handle member may be formed of materials or in such amanner as to provide one or more operational or functionalcharacteristics which differ from those which the handle member wouldhave if merely formed in the same manner of the same material as thestriking member. For example the handle may be formed from othermaterials such as titanium, aluminum, plastic or other appropriatematerial.

Referring to FIG. 6, in a one embodiment the handle member includesmultiple tubular composite layers as indicated generally at 60-66. Thelayers 60-66 are disposed adjacent each other and are arranged in asubstantially concentric manner. The number of layers must be sufficientto withstand the swinging action of the bat, a gripping force appliedthereto by a user, and the bending force imposed thereon when strikingwith the bat. However, preferably only the number of layers necessary towithstand such stresses would be provided, since more layers will addadditional weight to the handle member. The number, position, andorientation of the multiple layers will vary depending upon the size andtype of bat used. In one embodiment, the handle member may include theseven layers, 60-66, as shown. The number and thickness of layers andtheir position, and orientation may vary as needed to provide desiredflexibility or stiffness and to withstand gripping forces and hittingstresses.

Each composite layer in the embodiment illustrated includes structuralmaterial to provide structural stability and matrix material to supportthe structural material. The structural material may be a series offibers supported within the matrix material. Most of the layers includefibers that preferably extend substantially longitudinally of the handlemember. When the bat strikes a ball, the greatest stress component onthe handle member may be in bending, thus the majority of the fiberspreferably are directed longitudinally to withstand these stresses. Forexample, the even numbered layers 60, 62, 64, 66 may be longitudinallyextending layers, whereas odd numbered layers 61, 63, 65, which arefewer in number, may be circumferentially disposed layers. Thelongitudinally extending layers often are referred to as longitudinal,or 0° layers, since they have fibers that are directed substantiallyparallel to the longitudinal axis. The other layers may be what aretermed 90° layers, or circumferential layers, since they have fibers, inwhich the majority thereof are directed at substantially 90° relative tothe longitudinal axis. Specific layers may be constructed with fibersdirected at substantially 90° relative to the longitudinal axis andother fibers directed at substantially 0° and woven together within eachlayer. Or the layers may be uni-directional layers wherein the fiberswithin the layers are parallel.

In this embodiment, the layers include carbon fibers. However the fiberscould be other type of known fiber material, such as, but not limitedto, Kevlar™, boron, or fiberglass. A metallic mesh also might be used.

The matrix in the layers preferably is sufficiently durable and hassufficiently high adhesion properties to continue supporting thestructural material even after repeated use. In a preferred embodiment,the matrix material is a toughened epoxy. Alternatively, the matrix canbe some other thermally setting resin such as a polyester or vinylester. A person skilled in the art will appreciate that a thermoplasticresin can be used, rather than a thermally setting resin.

In particularly preferred embodiments, the handle member 30 has a weightof about 158 grams and is formed with the number of layers between 28 to40, wherein the weight of each layer varies from 0.6 to 14.0 grams. Atleast one layer of such embodiments is a braided layer having apercentage of the fibers within the braided layer extendinglongitudinally and the remaining fibers of the braided layer extendingsubstantially circumferentially. Also, from 1 to 4 layers are formedwith non-woven or non-braided fibers extending in two separatedirections, such as, for example, 0 degrees and 90 degrees.

Additionally, in particularly preferred embodiments, the handle member30 includes between 2 and 10 layers having longitudinally extendingfibers. In particularly preferred embodiments, the handle member 30includes a plurality of layers having helically extending fibers atvarious angles relative to the longitudinal axis, such as, for example,between 10 and 16 layers extend at plus or minus 30 degrees from thelongitudinal axis, between 6 and 16 layers extend at plus or minus 45degrees from the longitudinal axis, and 2 or less layers extend at plusor minus 60 degrees from the longitudinal axis.

Also, in particularly preferred embodiments, between 3 and 24 layers areformed of carbon fibers and between 13 and 25 layers are formed offiberglass fibers. The layers are formed in a variety of differentlengths varying from 5 cm to 67 cm. The layers, which are less than 67cm, are placed at varying positions along the full length of the handlemember. The layers are also formed in a variety of different widthsranging between 3.3 and 17.5 cm. Other layers have widths that varyalong their length from between 0 to 17.5 cm. The number of layershaving widths that vary along their length range between 8 and 11layers. The fibers within layers are formed with an area fiber densityof between 0.0143 and 0.048 grams/cm², and each layer can be formed witha weight in a range of 0.6 to 14 grams.

In alternative preferred embodiments, one or more of the characteristicsof the handle member can be altered, such as, for example: the weight,size, thickness and stiffness of the handle member; the number, size,composition and orientation of the layers; and the composition, density,and orientation of the fibers within a layer. The handle memberpreferably has a weight within a range of 3 to 8 ounces. The handlemember 30 can be formed without a braided layer or with an alternatenumber of braided layers. The handle member 30 can be formed with fiveor more layers of fibers wherein the non-woven fibers extend in twodirections or with no such layers. Two or more of the layers can includeother combinations of longitudinally, circumferentially and helicallyextending fibers. The handle member can be formed of multiple layershaving helically extending fibers wherein any one layer can have fibersextending between plus or minus 1 to 89 degrees from the longitudinalaxis. The fibers within the layers can be formed of other materials,such as, for example, glass, boron, graphite or other metal.

FIG. 10 is a simplified illustration of the manner in which multiplelayers of fiber composite material may be assembled. As is shown some ofthe layers extend the full length of the handle (layers 90 a, b, c, d),while others are shorter and reside in selected regions of the handlemember (90 e, f, g, h, i, j, k). Only a limited number of layers areshown in FIG. 10, for the sake of simplicity in the illustration.

The handle member includes a proximal gripping portion and a distaltapered portion, wherein one of the proximal gripping portion and thedistal tapered portion is formed with a larger number of layers than theremaining portion. The characteristics of the handle member thereforecan vary over its length.

The handle member 30, when formed of a composite material and producedin accordance with the present invention, can be produced with astiffness, or resistance to bending along the longitudinal axis 20 ofthe bat 10, within the range of 200 to 1980 lbs/in. Preferably, thehandle member 30 is formed with a stiffness or resistance to bendingwithin the range of 400-900 lbs/in. (The term “lbs/in.” refers to theamount of force in pounds applied perpendicular to the member to produceon inch of deflection in a test method described below.)

Referring to FIG. 11, the stiffness of the handle member 30 isdetermined through a three-point bend stiffness test wherein the handlemember is placed upon first and second supports 90 and 92 of a universaltest machine, or similar test machine, such as the universal testmachine produced by Tinius Olsen Testing Machine Co., Inc. of WillowGrove, Pa. The first support 90 is a V-block support positioned at thedistal end 30 a of the handle member 30. The V-block supportconfiguration of the first support 90 also serves to inhibit bothlongitudinal and transverse movement of the distal end 30 a of thehandle member 30. The second support 92 is a roller support including aroller 94 rotatable about a horizontal axis 96 spaced from V-blocksupport 90 and positioned near the proximal end 30 b of the handlemember 30. For handle members 30 greater than or equal to 19 inches, thesecond support 92 is positioned a distance D₆ of 19 inches from support90. The second support 92 also supports the handle member 30 in a firstdirection, preferably by maintaining the proximal end such that thelongitudinal axis 20 of the bat 10 is in a horizontal position. Thesecond support 92 enables the proximal end 30 b to move longitudinally.

The third point of the bend stiffness test is provided by a crosshead100 having a semi-circular shape. Preferably the semi-circular crossheadhas a radius of 2.0 inches. The crosshead is configured to extend in asecond direction opposite of the first direction. The crosshead may bemoved downwardly onto the horizontally positioned handle member 30 witha force noted F₁ imposed thereon. The crosshead is connected to a loadcell (not shown) which includes a strain gauge for measuring the loadapplied to the crosshead during displacement of the crosshead. Thecrosshead 100 is positioned a distance D₇ from the first support 90.Distance D₇ is in a range of 30% to 40% of distance D₆ and morepreferably 7 inches, such that the semicircular crosshead contacts thehandle member at a location approximately 7.0 inches from the distal end30 a of the handle member 30.

During testing, the handle member is positioned as described above. Thecrosshead is driven in the second direction at a speed of 1.0 inches perminute. As the crosshead moves in the second direction (i.e., downwardlyin FIG. 12) the testing machine with input from the load cell calculatesthe load (F₁) per the lateral deflection, or displacement, of the handlemember 30.

Referring to FIG. 12, the three-point bend stiffness test also can beperformed on an assembled bat. When testing a bat the first support 92is positioned such that a proximal side of the first support lies adistance D₈, which may be approximately 6 inches, from the distal end 12b of the striking member 12, and the second support 92 is positioned adistance D₉, which may be approximately 6 inches, from the proximal end30 b of the handle member 30. The distance between supports 90, 92 isnoted at D₁₀ and the cross head is positioned a distance D₁₀ fromsupport 92 which is approximately one half D₁₀ so as to contact the batat a point between and equi-distant from the first and second supports.

During testing, the bat 10 is positioned as described above. Thecrosshead is driven in the second direction (downwardly in FIG. 12) at aspeed of 0.5 inches per minute. As the crosshead moves in the seconddirection, the testing machine with input from the load cell calculatesthe load per displacement of the bat.

The bat 10 of the present invention can be formed such that thestiffness of the bat 10 is within the range of 400 to 2500 lbs/in. Inparticularly preferred embodiments, the bat 10 is formed with astiffness, or resistance to bending, within the range of 500 to 1500lbs/in, and more preferably in a range of 400-900 lbs/in. A conventionalaluminum bat typically has a stiffness, or resistance to bending, ofapproximately 2200 to 2500 lbs/in.

The present invention enables the bat to be produced with significantlyless stiffness and greater flexibility without negatively affecting thebatting performance of the bat. The present invention enables one ofordinary skill in the art to vary the composition of the bat to producea bat that is optimally configured, adjusted or tuned to meet the needsof a particular player. The present invention enables one of ordinaryskill in the art to produce a bat that optimizes flexibility and,through the direct connection between the handle member and the strikingmember, maximizes energy transfer between the handle and strikingmembers, and the power output of the bat.

It should be noted that examples set out herein are only exemplary innature, and should not be considered limiting as to the structure andmethod of manufacture of bats according to the invention. For example,although the bat has been described with a metal striking member and acomposite handle member, such a wide difference in materials for the twomembers may not be necessary. For example, the striking member and thehandle member both may be made of composite material, but withconstructions which provide varying operational or functionalcharacteristics beneficial for the specific portion of the bat whichthey form.

In constructing the bat of the illustrated embodiment the strikingmember 12 may be formed as set out above. End 12 b initially remainscylindrical, without the bent over portion as illustrated in FIG. 1.

The tubular handle member may be formed by wrapping sheets ofpreimpregnated composite material on a mandrel. A first layer is wrappedon the mandrel, followed by a second layer, etc., until the desirednumber of layers have been wrapped on the mandrel in the desiredpositions and orientations to form the tubular handle member. Themandrel has a configuration which produces both the elongatesubstantially cylindrical gripping portion 32 and the divergingfrusto-conical juncture section 34.

To form projecting ribs 40, and referring to FIGS. 7-9, after asufficient number of layers of preimpregnated composite material havebeen wrapped onto the mandrel, a plurality of forming members indicatedgenerally at 70, 72, 74 having a selected arcuate configuration areplaced on the outside of the juncture section of the handle member whilethe composite material is still malleable. FIG. 7 shows members 70, 72,74 prior to placement on the outside of the juncture section 34 and theplacement of such is illustrated in dashed outline in FIG. 7. As is seenmembers 70, 72, 74 do not extend fully about the juncture section whenplaced thereon, but instead have gaps therebetween.

Members 70, 72, 74 have a thickness substantially equal to the desiredprojection for ribs 40 and the space between adjacent edges of elements70, 72, 74 is the desired width of ribs 40.

As mentioned previously the projections may be in forms other thanelongate ribs and other molding or forming members may be provided toachieve the desired projection configurations.

When the forming members are placed against the juncture section asnoted, the tubular member then may be wrapped in shrink tape and placedin an oven between 250 and 300° F. for about 45 minutes to one hour. Theshrink tape preferably is temperature resistant and has high shrinkageand compaction capability when heated. As the shrink tape contracts itpresses the composite layers into a desired configuration about theforming mandrel and presses members 70, 72, 74 into the compositematerial as seen in FIG. 8 to form depressions between areas whichbecome projecting ribs 40. The depressions are indicated generally at76, 78, 80, respectively, having a depth equal to the thickness ofmembers 70, 72, 74. FIG. 9 illustrates the configuration thus producedwhen members 70, 72, 74 are removed.

Heating the handle member speeds the curing process, but it may beallowed to cure at a lower temperature for a longer period of time. Forexample, the handle member may be allowed to cure at room temperaturefor several days. The pressure applied by the shrink tape may range from15 to 150 psi depending both on the type of the shrink tape used and theflow properties of the matrix material used. Alternately, some otherknown apparatus may be used to pressurize the handle member duringcuring, such as a bladder or a vacuum bag.

The handle member (or striking member if chosen to do so) also may beformed of a chopped fiber slurry. The chopped fibers can be carbon,glass, fiberglass, boron, or various metals.

Although not illustrated in the figures, it should be recognized thatother methods may be used for forming the handle and providing a desiredseries of projections thereon. One method of doing so is to wrap sheetsof pre-impregnated composite material onto a mandrel as previouslydescribed to form the general configuration for the handle with itscylindrical gripping portion and flared frusto-conical juncture section.The materials wrapped on the mandrel then may be placed in a clam shellstyle mold having the desired external configuration for the handle,including forms to produce a selected pattern of projections thereon.After the clam shell mold has been placed about the exterior of thehandle, the forming mandrel is removed, a pressure bladder is insertedwhere the mandrel previously had been, and pressure is applied on thebladder to force the wrapped materials outwardly against the mold. Thematerials then are allowed to cure and are removed from the mold withthe desired external configuration.

Although the handle member has been described using a plurality ofsheets of impregnated composite material, the layers may be formed bysome other method, such as a filament winding process. With a filamentwinding process, a continuous fiber, rather than a preimpregnated sheetas described above, is wrapped around a mandrel. The filament windingprocess may use a preimpregnated fiber. Alternately, the continuousfiber may run through a resin bath before it is wrapped onto themandrel. The filament winding process typically winds the fiber in ahelical path along the mandrel, making it difficult to produce a layerhaving fibers that are exactly 90 degrees relative to the longitudinalaxis of the layers. Thus the layers may include layers that are at anangle substantially 90 degrees, but not exactly at 90 degrees.

The handle member, being produced of composite material, permitsselective production to obtain a handle member of the desired weightwhile still obtaining the necessary strength and stiffness.

After the handle member has been formed it is inserted through the openend 12 b of striking member 12, such that gripping portion 32 extendslongitudinally outwardly from end 12 a of the striking member. Prior toinserting the handle member a layer of adhesive is applied either to theouter surface of juncture section 34 of the handle member or the innersurface of juncture section 14 of the striking member. The strikingmember 12 and handle 30 are urged in opposite directions along thelongitudinal axis, such that the juncture section 34 of the handlemember is forced into tight engagement with the interior surface ofjuncture section 16. As this occurs, the adhesive applied between theparts is pressed into recesses 76, 78, 80 and ribs 40, or otherprojections, firmly contact, or engage, the inner surface of juncturesection 16. Excess adhesive will be allowed to flow outwardly from end30 a of the handle member, with only the selected thickness of adhesiveremaining.

It has been found that an adhesive such as Scotch-Weld™ DP-100 epoxyadhesive or PT 1000 urethane adhesive from Willamette Valley Co., ofEugene, Oreg., works well in this application. Other appropriateadhesives also may be used. In a preferred embodiment, projections 40extend outwardly from remainder portions of the outer surface of thejuncture section of the handle member in a range of 0.001 to 0.010 inch,and more preferably in a range of 0.002 to 0.005 inch and have a widthin a range of 0.125 to 0.75 inch and more preferably in a range of 0.2to 0.3 inch. The layer of adhesive will have a thickness generally equalto height of the projections and is allowed to cure and form asubstantially rigid, firm interconnection between the striking memberand the handle member. The substantially rigid interconnection betweenthe juncture sections of the striking member and handle member providedby the adhesive and direct engagement of the projections with the innersurface of the striking member permits substantially complete strikingenergy transfer between the handle member and the striking member.

After the handle member has been secured to the striking member, insert22 is inserted into the striking member, the outer end 12 b is rolledover into the configuration illustrated in FIG. 1, and stop member 50 isinserted therein. Transition member 52 (when used) is attached toprovide a smooth transition between the inner end 12 a of the strikingmember and handle 30.

Prior to, or following, assembly of the handle member and strikingmember, weighted member, or plug, 54 is inserted and secured in theproximal end portion of the handle member as shown in FIG. 1.

Weighted plug 54 is a generally cylindrical member coupled to theproximal end 30 b of the handle member 30. The weighted plug preferablyis sized to fit snugly within the proximal end 30 b of the handle member30 and preferably is affixed to the proximal end 30 b with a suitableadhesive. Alternative means for coupling the plug 54 to the proximal end30 b of the handle member 30 also are contemplated, such as, forexample, press-fit connections, fasteners, and other mechanical latchingmechanisms. The weighted plug 54 is formed of a relatively densematerial, preferably a metal. Alternatively, the weighted plug 54 can beformed of other materials, such as, for example, sand, a fluid or apolymeric material. The plug 54 is formed with a weight in the range of0.5 to 7.0 ounces, and preferably within a range of 2 to 5 ounces, and alength in the range of 1.0 to 4.0 inches.

The weighted plug 54 places additional weight, or mass, generallydirectly beneath the player's grip during swinging, thereby facilitatingthe player's ability to swing the bat and to increase his or her batspeed. The weighted plug 54 provides the player with a pivot point,which facilitates rotation of the bat about the mass or grip location ofthe player.

Additionally, the weighted plug 54 also serves to dampen, orsubstantially reduce, the shock, vibration and “sting” commonly felt bya player when hitting a ball, particularly when the ball is hit awayfrom a desired hitting region of the striking member, or the “sweetspot.” The weighted plug 54 serves as a vibration sink thatsubstantially lowers the amplitude of the vibrational energy generatedupon impact of the bat 10 with a ball at the location of the plug 54thereby reducing the vibration or shock felt by the player. In anotheralternative preferred embodiment, the plug 54 is integrally formed withthe knob 48.

The use of the weighted plug 54 is just one example of the advantagesachieved in the present invention from redistributing the weight, ormass, within the bat 10 through decoupling of the handle member 30 andthe striking member 12. When forming the handle member 30 of a compositematerial, the weight of the handle member 30 can be reduced from that ofa conventional metal handle member. This weight can then beredistributed to other locations on the bat, such as at the proximal endof the handle member 30 to improve, or tune, the performance of the bat10. In the present invention, the weighted plug 54 can be added to thebat 10 to enable the player to increase his or her bat speed, and toreduce the shock and vibration felt by the user, without excessively orunnecessarily increasing the weight of the bat 10. In anotheralternative preferred embodiment, weight can be redistributed to thestriking member 12.

The method described herein and the bat produced provide a bat which hasimproved striking capabilities. Such improved striking capabilities areprovided by the structural characteristics of the bat. In one instanceincreased bat swing speed is allowed by producing a bat with a handlewhich is lighter than would be the case if it were made of the samematerial or in a manner similar to the striking portion of the bat. Thisreduction in weight of the handle in relation to the striking portionand providing a substantially rigid interconnection between the twopermits increased bat speed and substantially complete striking energytransfer between the striking member and the handle member. Further itprovides desirable weight distribution in the bat with the greatesteffective mass in the striking region and lower effective mass in thehandle.

It also has been found that the slugging, or hitting, characteristics ofthe bat may be varied by mating various composite handle members withstriking members of different materials or configurations, with asubstantially rigid interconnection therebetween. Thus different modelsof bats may be produced, tuned to selected requirements.

By providing a bat constructed with an independently produced strikingmember and handle member which are rigidly interconnected at a junctureregion, bats may be made with numerous selected functionalcharacteristics. The striking member may be made of materials whichprovide optimum ball striking effectiveness, while the handle member maybe constructed in such a fashion that is allows the batter to impart themaximum possible force from the batter's hands to the bat and to producethe greatest swing speed. The handle member may be laid up from avariety of composite materials with selected thicknesses, orientations,and positions within the handle member to produce desired strength,weight, stiffness, etc., in the overall handle or even within selectedregions of the handle.

Explaining further, selected regions of the handle may have a greater orlesser number of layers of composite material than other regions, thethicknesses or structural materials within the layers may vary atdifferent regions of the handle member, and other characteristics may bevaried through selected lay up of materials in the handle member duringproduction.

As an example of desirable differences in handle members which may beformed, it has been found that certain bats, such as for softball use,will work better with a stiffer handle member, whereas for baseball amore flexible, or less stiff, handle member is preferable.

With the structure and method for producing such set out herein, a batmay be optimized for the selected usage by selection of materials andlay up for the various components of the bat.

While there have been illustrated and described preferred embodiments ofthe present invention, it should be appreciated that numerous changesand modifications may occur to those skilled in the art and it isintended in the appended claims to cover all of those changes andmodifications which fall within the spirit and scope of the presentinvention.

What is claimed is:
 1. An elongate bat having a longitudinal axiscomprising: an elongate one-piece tubular striking member having a firstlength, a distal end, a proximal end, a striking region intermediatesaid distal and proximal ends, and a first juncture section adjacentsaid proximal end conversing toward said axis on progressing toward saidproximal end, said striking member having a first effective mass; and anelongate one-piece handle member shorter than said first length composedof a material having a second effective mass which is different fromsaid first effective mass, said handle member having a distal end, asecond juncture section adjacent the distal end of the handle member, aproximal end, and a gripping portion between the second juncture sectionand the proximal end of the handle member, the second juncture sectionhaving an outer diameter that is greater than the outer diameter of thegripping portion, the second juncture section being firmly joined to thefirst juncture section of said striking member, such that at least aportion of the first juncture section directly contacts at least aportion of the second juncture section, to provide a rigidinterconnection there between to permit substantially complete strikingenergy transfer between said handle member and said striking member, thestriking member being formed of a fiber composite material comprising aplurality of tubular layers, each layer comprises a matrix includingstructural fibers supported by the matrix, the plurality of tubularlayers including fiber layer configurations selected from the groupconsisting of a layer of longitudinally extending fibers, a layer ofcircumferentially extending fibers, a layer of helically extendingfibers, a layer of braided fibers, and combinations thereof, and thelength of the second juncture section, which is overlapped by the firstjuncture section, being less than thirty percent of the total length ofthe handle member.
 2. A bat for striking a ball, the bat comprising: anelongate tubular striking member extending along a longitudinal axis andhaving a distal end, and a proximal end, the striking member including afirst juncture section integrally formed with the striking member andpositioned adjacent the proximal end of the striking member, thestriking member being formed of a first material; and an elongatetubular handle member extending along the longitudinal axis and having adistal end and a proximal end, the handle member including a secondjuncture section integrally formed with the handle member and positionedadjacent the distal end of the handle member, the handle member coupledto the striking member such that at least a portion of the firstjuncture section firmly and directly contacts at least a portion of thesecond juncture section, the handle member having a resistance tobending along the longitudinal axis in the range of 200-1980 lbs/inthree-point bend stiffness test wherein the handle member istransversely supported in a first direction by a pair of supports spacedapart a selected distance, with the first support adjacent the distalend and a second support adjacent the proximal end, and is transverselyloaded in a second direction, opposite the first direction, at alocation on the handle member in a region between 30% and 40% of saidselected distance from the distal end of the handle member.
 3. The batof claim 2, wherein the handle member has a resistance to bending alongthe longitudinal axis in the range of 400-900 lbs/in.
 4. The bat ofclaim 2, wherein the handle member has a length in the range of 9 to 22inches, and wherein the handle member has a weight in the range of 3 to8 ounces.
 5. The bat of claim 4, wherein the handle member has a weightin the range of 5 to 7 ounces.
 6. The bat of claim 2, wherein thestriking member is formed from a material selected from the groupconsisting of a metal, wood, a ceramic, and a fiber composite material.7. The bat of claim 2, wherein the handle member is formed of a fibercomposite material comprising a plurality of tubular layers, whereineach layer comprises a matrix including structural fibers supported bythe matrix, and wherein the plurality of tubular layers includes fiberlayer configurations selected from the group consisting of a layer oflongitudinally extending fibers, a layer of circumferentially extendingfibers, a layer of helically extending fibers, a layer of braidedfibers, and combinations thereof.
 8. The bat of claim 7, wherein thehelically extending fibers of the at least one layer of helicallyextending fibers extend along the handle member at an angle that isbetween +/−1 to 89 degrees from the longitudinal axis.
 9. The bat ofclaim 7, wherein the handle member includes a proximal gripping portionand a distal tapered portion, wherein one of the proximal grippingportion and the distal tapered portion is formed with a larger number oflayers than the remaining portion.
 10. The bat of claim 2, wherein thecomposite material of the handle member comprises a chopped fiberslurry.
 11. The bat of claim 2, further comprising a weighted plugcoupled to the proximal end of the handle member, and wherein the lengthof the second juncture section, which is overlapped by the firstjuncture section, is less than thirty percent of the total length of thehandle member.
 12. The bat of claim 11, wherein the weighted plug weighsin the range of 2 to 5 ounces.
 13. The bat of claim 11, wherein theweighted plug has a length in the range of 1.0 to 4.0 inches.
 14. Thebat of claim 7, wherein the fibers are formed of a material selectedfrom the group consisting of glass, fiberglass, carbon, boron, metal andcombinations thereof.
 15. The bat of claim 7, wherein the fibers have anarea fiber density within the range of 0.0143 and 0.048 grams/cm². 16.The bat of claim 7, wherein the first material has a greater impactresistance to ball strikes than the composite material of the handlemember.
 17. The bat of claim 2, wherein at least one of an outer surfaceof the juncture section of the handle member and an inner surface of thejuncture section of the striking member has a plurality of projectionswhich extend radially a predetermined distance.
 18. A bat for striking aball, the bat comprising: an elongate tubular striking member extendingalong a longitudinal axis and having a distal end, a proximal end, and afirst juncture section adjacent the proximal end of the striking member,the striking member being formed of a first material; and a one-pieceelongate tubular handle member extending along the longitudinal axis andhaving a distal end, a proximal end and a second juncture sectionadjacent the distal end of the handle, the handle member coupled to thestriking member such that at least a portion of the first juncturesection firmly and directly contacts at least a portion of the secondjuncture section; the bat having a resistance to bending along thelongitudinal axis in the range of 500 to 2100 lbs/in a three-point bendstiffness test wherein the bat is transversely supported in a firstdirection at a first location 6 inches from the distal end of thestriking member and a second location 6 inches from the proximal end ofthe handle member, and is transversely loaded in a second direction,opposite the first direction, at a third location at mid-length positionon the bat.
 19. The bat of claim 18, wherein the bat has a resistance tobending along the longitudinal axis in the range of 500-1500 lbs/in. 20.The bat of claim 18, wherein the handle member has a length in the rangeof 9 to 22 inches, and wherein the handle member has a weight in therange of 3 to 8 ounces.
 21. The bat of claim 18, wherein the handlemember has a weight in the range of 5 to 7 ounces.
 22. The bat of claim18, wherein the striking member is formed from material selected fromthe group consisting of a metal, wood, a ceramic, and a fiber compositematerial.
 23. The bat of claim 18, wherein the handle member is formedof a fiber composite material comprising a plurality of tubular layers,wherein each layer comprises a matrix including structural fiberssupported by the matrix, and wherein the plurality of tubular layersincludes fiber layer configurations selected from the group consistingof a layer of longitudinally extending fibers, a layer ofcircumferentially extending fibers, a layer of helically extendingfibers, a layer of braided fibers, and combinations thereof.
 24. The batof claim 23, wherein the handle member includes a proximal grippingportion and a distal tapered portion, wherein one of the proximalgripping portion and the distal tapered portion is formed with a largernumber of layers than the remaining portion.
 25. The bat of claim 23,wherein the composite material of the handle member comprises a choppedfiber slurry.
 26. The bat of claim 18, further comprising a weightedplug coupled to the proximal end of the handle member, and wherein thelength of the second juncture section, which is overlapped by the firstjuncture section, is less than thirty percent of the total length of thehandle member.
 27. The bat of claim 26, wherein the weighted plug weighsin the range of 2 to 5 ounces.
 28. The bat of claim 26, wherein theweighted plug has a length in the range of 1.0 to 4.0 inches.
 29. Thebat of claim 23, wherein the fibers have an area fiber density withinthe range of 0.0143 and 0.048 grams/cm².
 30. The bat of claim 23,wherein the first material has a greater impact resistance to ballstrikes than the composite material of the handle member.
 31. The bat ofclaim 18, wherein at least one of an outer surface of the juncturesection of the handle member and an inner surface of the juncturesection of the striking member has a plurality of projections whichextend radially a predetermined distance.